The invention relates to a power supply means for electrically operated moving apparatuses such as mining equipment, comprising
a trolley track comprising busbars and positioned at least over a portion of its length above a space where the apparatuses move;
trolleys movable on the trolley track, the trolleys comprising contacts arranged in contact with the busbars and each being connected to the respective apparatus by means of an electric cable with adjustable length; and
at least one turntable-type switch installed in the trolley track above the space where the apparatuses move and comprising a coupling portion forming part of the trolley track, whereby, when extending in the same direction as the trolley track in alignment with it, the coupling portion forms together with the trolley track a continuous trolley track along which the trolley is movable and which is pivotable about a vertical axis away from the trolley track to another position, whereby the trolley is turnable by means of the switch to another position together with the coupling portion when it reaches the switch.
The invention is also concerned with a turntable-type switch for a power supply means intended for electrically operated moving apparatuses, the power supply means comprising
a trolley track comprising busbars and positioned at least over a portion of its length above a space where the apparatuses move;
trolleys movable on the trolley track, the trolleys comprising contacts arranged in contact with the busbars and each being connected to the respective apparatus by means of an electric cable with adjustable length; the switch comprising a coupling portion forming part of the trolley track, whereby, when extending in the same direction as the trolley track in alignment with it, the coupling portion forms together with the trolley track a continuous trolley track along which the trolley is movable and which is pivotable about a vertical axis away from the trolley track to another position, whereby the trolley is turnable by means of the switch to another position together with the coupling portion when it reaches the switch.
In a trolley system intended for the power supply of various vehicles and machines, electric current is applied to the point of application from busbars positioned in a trolley track in the ceiling of a space where the vehicles or machine move. In addition to busbars, the trolley system comprises a roller race on which a trolley supporting slide contacts in contact with the busbars is movable. From the trolley a cable leads to the apparatus utilizing the current. When the apparatus moves on, the trolley slides along its roller race while the slide contacts make contact with the busbars, thus conducting current to the apparatus through the cable.
Various conditions require trolley track structures and switches of different types, in order that several apparatuses could utilize the same trolley track. It is a fairly common practice to use a single trolley track comprising required busbars, switches being installed at junctions for shunting the trolley to an intersecting trolley track. When, for instance, the track is branched or there are several moving apparatuses, it is necessary to provide switches and in some cases a shunting track of sufficient length for trolleys moving in opposite directions. Trolley switches known in the prior art include a bending switch, a guillotine switch to be displaced aside and a turntable switch.
In the bending switch, the switching is carried out by bending a portion of the trolley track to an other position; this kind of switch is today fairly common in mining use. The arrangement is simple and reliable in operation, but it has many disadvantages. Strains caused by the bending weaken the structure in the long run, which involves a safety risk. Furthermore, rather a long portion of the track, typically 7 to 8 meters, has to be bent to achieve the required sideward displacement, wherefore the switch is unreasonably long in practice. The length of the busbars changes on bending, which causes installation problems. Moreover, in cases where a shunting place has to be provided, the required construction, comprising two switches and an additional track, is more than 20 meters in length, which is difficult to realize and expensive to construct. When using the bending switch, it is not possible to construct a turning loop at the end of the trolley track, because the turning loop would reverse the phase sequence of the busbars.
The guillotine switch comprises a coupling portion movable in the transverse direction of the trolley track. The coupling portion comprises a straight and a curved track portion side by side. Switching takes place by displacing the coupling portion, so that either one of the track portions will form an extension of the main track, depending on the position of the coupling portion. In principle, this arrangement is also simple but has a number of disadvantages. The structure is difficult to realize and unreliable in operation. At various junctions and shunting places, the installation and operation of this arrangement are difficult if not impossible because, for instance, it cannot be used with intersecting tracks. With this switch structure, the end of the track cannot be formed into a loop as the phase sequence of the busbars would be reversed. The structure is difficult to modify and additional bends are formed in the track when the structure is used.
The turntable switch comprises a pivotal turntable to which a straight track portion is attached. Switching takes place by revolving the turntable so that the track portion forms an extension of the desired track. This switch is reliable in operation and takes up little space, in addition to which it can be realized in a simple manner. A disadvantage is, however, that the end of the track cannot be formed into a loop, as the loop would reverse the phase sequence of the busbars. The structure is also difficult to modify and in certain cases it causes additional bends in the track. This switch cannot, either, be used as a shunting switch as only one trolley at a time can be positioned on the track portion of the switch.
The object of the present invention is to provide a power supply means and a switch by means of which various track arrangements are easy and simple to realize and by means of which the end of a trolley track can be formed into a loop so that the apparatus to be supplied with power can perform a turning movement and return easily and simply and in which the switch may simultaneously operate as a shunting switch without unnecessarily retarding meeting apparatuses or causing them to stop.
The power supply means of the invention is characterized in that
the switch comprises two parallel coupling portions positioned reversely symmetrically with respect to the turning axis of the turntable;
the phase sequence of the busbars of the coupling portions is correspondingly reversely symmetrical with respect to the turning axis;
the coupling portions are so spaced apart from each other that a trolley can be positioned simultaneously on both coupling portions: and
both coupling portions of the switch are turnable in alignment with the rest of the trolley track so as to form a continuous trolley track.
The switch of the invention is characterized in that
the switch comprises two parallel coupling portions positioned reversely symmetrically with respect to the turning axis of the turntable;
the phase sequence of the busbars of the coupling portions is correspondingly reversely symmetrical with respect to the turning axis;
the coupling portions are so spaced apart from each other that a trolley can be positioned simultaneously on both coupling portions; and
both coupling portions of the switch are turnable in alignment with the rest of the trolley track so as to form a continuous trolley track.
The basic idea of the invention is that the switch is a turntable-type switch comprising two coupling portions positioned reversely symmetrically with respect to the turning centre in such a way that the phase sequence of the busbars is correspondingly reversely symmetrical. When two apparatuses meet each other, the switch is turned after the trolley of one apparatus has reached the switch so that the trolley is shunted from the main track and the trolley of the other apparatus is able to drive through the switch without stopping, whereafter the first trolley is shunted back to the main track, and it can move on. Correspondingly, the switch can be installed in connection with the end loop of the trolley track. After the trolley has moved around the loop, it is shunted back to the main trolley track and the voltage phases of the busbars and, as a consequence, those of the trolley remain unchanged.